2) Teach musicians to use proper vocal microphone technique.
Last Saturday, I taught a 4-hour audio training course at a local church. I explained that anyone using a vocal microphone needs to hold the microphone right up to their mouth.
Immediately, two of the people in the class started talking about how certain people would start with the microphone up to their mouth and slowly lower it as the song went on.
They’d have to turn up the gain until…SCREEEEEEEEEEEEECH!
Those using vocal microphones need to know that audio equipment has its limitations. Therefore, explain to the singers that if they lower their microphones their voices will drop out of the mix.
It’s a bit easier regarding people using vocal microphones for speaking roles. The problem I’ve observed is, like the singers, they slowly lower the microphone.
As they’re using the microphone for a speaking role and will likely be holding a Bible, book, or piece of paper, set up a vocal microphone on a stand for them. Have them read a bit after the sound check to set the gain.
*Tip: If you have more than one person talking into the same vocal microphone during the service, make note of their natural speaking volume level. This way, when they walk up to the microphone, you can lower the fader before they speak those first words.
3) Use the proper gain setting technique.
Setting the channel gain for any sound source, you want the clearest strongest signal. You want the best signal-to-noise ratio so that the sound, such as the singer’s voice, is stronger than any line noise that might exist. However, you don’t want to allow for so much gain that you allow for feedback in the system.
An easy way to get the best signal-to-noise ratio is by using the “gain-before-feedback method” of gain setting. As you turn up the gain, with the fader at 0, turn it up until you get feedback. Then turn down the gain a few notches.
Personally, I set the fader at zero and turn up the gain until the sound is about at the volume where I want it in the room. But if I do experience feedback, I know to turn back the gain.
The Take Away
If you’re having more than your share of feedback during an event, consider more than one issue might be the problem. Feedback prevention comes down to placing microphones in the right relationship to monitors and loudspeakers, ensuring that microphones are as close to the sound source as possible, and that you’re sending the right amount of the audio signal into the mixer.
One last very important piece of information. As I told my class on Saturday, the entire sanctuary is your responsibility. This means everything from the stage to the sound booth.
So the next time you experience a feedback issue and are asked about it after the service, don’t place blame on someone else or some piece of equipment. Take ownership of it, apologize for it, and do what you can to prevent it from happening again.
Ready to learn and laugh? Chris Huff writes about the world of church audio at Behind The Mixer. He covers everything from audio fundamentals to dealing with musicians. He can even tell you the signs the sound guy is having a mental breakdown.